Problem with image texture name in image node that not match with the texture being used in the model
I think you are confusing the name of the file, and the name of the texture slot inside Blender :



The name of the texture slot can be whatever you want (you can change it ie. in the Image Editor).

When you open a picture file, Blender automatically create a new slot and name it as the file. But, if you then change the file, the slot will keep it's old name, which can indeed be confusing.